Sidek Abdul Aziz

Effect of ZnO on the Physical Properties and Optical Band Gap of Soda Lime Silicate Glass

This manuscript reports on the physical properties and optical band gap of five samples of soda lime silicate (SLS) glass combined with zinc oxide (ZnO) that were prepared by a melting and quenching process. To understand the role of ZnO in this glass structure, the density, molar volume and optical band gaps were investigated. The density and absorption spectra in the Ultra-Violet-Visible (UV-Visible) region were recorded at room temperature. The results show that the densities of the glass samples increased as the ZnO weight percentage increased. The molar volume of the glasses shows the same trend as the density: the molar volume increased as the ZnO content increased. The optical band gaps were calculated from the absorption edge, and it was found that the optical band gap decreased from 3.20 to 2.32 eV as the ZnO concentration increased.

Fabrication and Crystallization of ZnO-SLS Glass Derived Willemite Glass-Ceramics as a Potential Material for Optics Applications

Willemite glass-ceramics were successfully derived from conventional melt-quench ZnO-SLS precursor glass by an isothermal heat treatment process. The effect of heat treatment temperatures on the physical properties was investigated by Archimedes principle and linear shrinkage. The generation of willemite crystal phase and morphology with increase in heat treatment temperature was examined by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and field emission scanning electron microscopy (FESEM) techniques. X-ray diffraction revealed that the metastable -Zn2SiO4 and thermodynamically stable zinc orthosilicate α-Zn2SiO4 phases can be observed at temperatures above 700°C. The experimental results indicated that the density and shrinkage of the glass-ceramic vary with increasing the sintering temperature. FTIR studies showed that the structure of glass-ceramic consists of SiO2 and ZnO4 units and exhibits the structural evolution of willemite glass-ceramics. The characteristic of strong vibrational bands can be related to the tetrahedron corresponding to reference spectra of willemite.

Effect of Sintering Temperature on Structural and Morphological Properties of Europium (III) Oxide Doped Willemite

Willemite- (Zn2SiO4-) based glass ceramics doped with various amounts of europium oxide (Eu2O3) were prepared by solid state melting and quenching method. Effect of sintering temperature (600–1000°C) on structural and morphological properties of the doped samples was investigated. Phase composition, phase evolution, functional groups, and microstructure analysis were, respectively, characterized using X-ray diffractometer (XRD), fourier transform infrared spectroscopy, field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray. XRD analysis detected the presence of rhombohedral crystalline phase in the doped samples sintered at different temperatures. FE-SEM and bulk density results confirmed that doping of the willemite with Eu2O3 effectively enhanced densification. The microstructural analysis of the doped samples showed that the average grain size increased with the increase of sintering temperature.

Effect of Milling Time on the Microstructure, Physical and Mechanical Properties of Al-Al2O3 Nanocomposite Synthesized by Ball Milling and Powder Metallurgy

The effect of milling time on the morphology, microstructure, physical and mechanical properties of pure Al-5 wt % Al2O3 (Al-5Al2O3) has been investigated. Al-5Al2O3 nanocomposites were fabricated using ball milling in a powder metallurgy route. The increase in the milling time resulted in the homogenous dispersion of 5 wt % Al2O3 nanoparticles, the reduction of particle clustering, and the reduction of distances between the composite particles. The significant grain refining during milling was revealed which showed as a reduction of particle size resulting from longer milling time. X-Ray diffraction (XRD) analysis of the nanocomposite powders also showed that designated ball milling contributes to the crystalline refining and accumulation of internal stress due to induced severe plastic deformation of the particles. It can be argued that these morphological and microstructural variations of nanocomposite powders induced by designated ball milling time was found to contribute to an improvement in the density, densification, micro-hardness (HV), nano-hardness (HN), and Young’s modulus (E) of Al-5Al2O3 nanocomposites. HV, HN, and E values of nanocomposites were increased by ~48%, 46%, and 40%, after 12 h of milling, respectively.

Study on Emission and Performance of Diesel Engine Using Castor Biodiesel

This paper presents the result of investigations carried out in studying the emission and performance of diesel engine using the castor biodiesel and its blend with diesel from 0% to 40% by volume. The acid-based catalyzed transesterification system was used to produce castor biodiesel and the highest yield of 82.5% was obtained under the optimized condition. The FTIR spectrum of castor biodiesel indicates the presence of C=O and C–O functional groups, which is due to the ester compound in biodiesel. The smoke emission test revealed that B40 (biodiesel blend with 40% biodiesel and 60% diesel) had the least black smoke compared to the conventional diesel. Diesel engine performance test indicated that the specific fuel consumption of biodiesel blend was increased sufficiently when the blending ratio was optimized. Thus, the reduction in exhaust emissions and reduction in brake-specific fuel consumption made the blends of caster seed oil (B20) a suitable alternative fuel for diesel and could help in controlling air pollution.

Studying the Effect of ZnO on Physical and Elastic Properties of (ZnO)x(P2O5)1−x Glasses Using Nondestructive Ultrasonic Method

Binary zinc phosphate glass system with composition of (ZnO)x(P2O5)1−x, ( = 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 mol%) was successfully prepared using a conventional melt-quenching method. Composition dependence of physical properties and elastic properties in the (ZnO)x(P2O5)1−x were discussed in association with the effects of adding zinc oxide (ZnO) as a modifier. The addition of ZnO modifier was expected to produce substantial changes on physical properties of the phosphate glasses. An increase in density values of the phosphate glasses was observed. Elastic moduli were studied by measuring ultrasonic longitudinal and shear velocities ( and ) of the glasses at room. Longitudinal modulus, shear modulus, bulk modulus, Young’s modulus, Poisson’s ratio, and Debye temperature were derived from both data of velocities and respective density of all of the samples. Findings from present work showed dependence of density and elastic moduli of each ZnO-P2O5 series on glass composition.

Optical Properties Changes of Ternary Glasses: Gamma Irradiation Effect

Research on tellurite based glass has become important because of it potential in photonic and shielding material. In this work, the changes of the optical properties of ternary tellurite glasses when radiated with 25kGy gamma ray dose were studied. Five glass samples, with composition [(TeO2)70 (B2O3)30]100-x (Bi2O3)x (where x = 5, 10, 15, 20 and 25 mol%) were prepared by melt quenching technique. The optical properties were studied by UV-Visible absorption. The X-Ray Diffraction (XRD) spectra result shows that all glass samples fit the amorphous state. The Fourier Transform Infrared Spectroscopy (FTIR) was used to explore the structural bonding in the prepared glass samples due to exposure. Gamma irradiation causes a profound change in the peak intensity as shown by FTIR spectra which is due to the breaking of the network bonding. Before gamma irradiation, the optical band gap, Eg value decreased from 2.50 eV to 2.30 eV with the addition of Bismuth content. The value kept decreasing (from 2.18 eV to 2.05 eV) following exposure to 25 kGy gamma irradiation due to the increase of non-bridging oxygen (NBO) and the increase of defect in the glass. The finding suggest that the glass with high content of Bi2O3 (25 Bi) give smallest Eg and show less changes (less defect) in FTIR spectra after gamma irradiation which indicate that this glass is more resistant to 25 kGy gamma irradiation dose compared to other glasses.

Design and development of learning management system at universiti Putra Malaysia: a case study of e-SPRINT

This paper reports the design and development of the e-SPRINT, Learning Management System, which has been derived from Sistem Pengurusan Rangkaian Integrasi Notakuliah dalam Talian - mod Elektronik) and currently being implemented at Universiti Putra Malaysia (UPM). The e-SPRINT was developed by utilizing PERL (Practical Extraction and Report Language) and was supported by standard database in Linux/UNIX environment operating system. The system is currently being used to supplement and complement part of the classroom-based teaching. This paper covers the architecture and features of the e-SPRINT system which consists of five main modules. Some general issues and challenges of such e-learning initiatives implementation will also be discussed.

Eddy Current Thermography Testing on Lack of Fusion (LOF) Defect of Carbon Steel Welded Sample

Eddy current thermography (ECT) employs the combination of conventional and advanced nondestructive testing (NDT) technique. This technology is capable to detect defect in subsurface of carbon steel welded sample of dimension 200 × 150 × 20 mm. The optimum joule heating process via eddy current distribution is 300A with the heat diffusion around 50–500 kHz (which is relatively high-frequency electromagnetic wave). Along with the emerging development of eddy current thermography, the infrared camera permits its radiation range to visualize the real-time image of the defect via the application of the thermoimager TIM software. The quantitative information about the defect will be acquired by the camera which is sensitive to the transient signal of heat through material under inspection. The analysis due to the geometrical shape, position, and length of lack of fusion (LOF) defect can be made through maximum amplitude temperature analysis. The investigation performs the temperature linescan graph of temperature amplitude via Matlab. The result obtained from ECT is compared to the error bar analysis in line with radiography technique. The studies demonstrate the effectiveness and reliability of the technique for the quantification analysis of lack of fusion (LOF) defect of welded sample.